1. Field of the Invention
This invention relates to a method for the manufacture of polybutadiene-modified polyesters, to polybutadiene-modified unsaturated polyester resin compositions and to a method for the manufacture of these resin compositions.
2. Description of Prior Arts
Heretofore, polybutadiene-modified unsaturated polyester resin compositions have been manufactured by reacting unsaturated acids including polybasic acids with a liquid hydrogenated polybutadiene having a hydroxy group at an end thereby forming polybutadiene-modified unsaturated polyesters and incorporating therein a polymerizable monomer possessing at least one double bond (Japanese Patent Publication No. 10672/1971). While these polybutadiene-modified unsaturated polyester resin compositions, on setting, give products which excel in water resistance, flexibility, bending property, etc., they have a disadvantage that they set slowly and exhibit poor miscibility with other unsaturated polyester resin compositions. When such compositions are applied to substrates, therefore, they dry slowly and require long standing before they become ready for polishing. Thus, they are hardly usable as cold setting paints. Moreover, they are not readily modified because they have poor miscibility with other unsaturated polyester resin compositions of the kind frequently used as agents for modifying workability and physical properties of other polymers. The excellent properties exhibited by cured products of these polybutadiene-modified unsaturated polyester resin compositions have not been utilized to advantage.
An object of this invention, therefore, is to provide a novel polybutadiene-modified unsaturated polyester, and a method for the manufacture thereof.
Another object of this invention is to provide polybutadiene-modified unsaturated polyester resin compositions which in themselves possess excellent setting property and drying property at room temperature and which are capable of producing set coats excelling in water resistance, flexibility and bending property.
A further object of this invention is to provide a method for the manufacture of polybutadiene-modified unsaturated polyester resin compositions of excellent properties as mentioned above.